Adam Gopnik on the current health of New York City. "This transformation is one you see on every street corner in Manhattan, and now in Brooklyn, too, where another local toy store or smoked-fish emporium disappears and another bank branch or mall store opens. For the first time in Manhattan's history, it has no bohemian frontier. Another bookstore closes, another theatre becomes a condo, another soulful place becomes a sealed residence. These are small things, but they are the small things that the city's soul clings to."